IOMM AGZ-5
AGZ 026B through 130B
61
Unit Test Mode
The unit test mode allows manual testing of controller outputs. Entering this mode
requires the following conditions.
Unit OFF input = OFF (i.e., entire chiller is shut down).
Manager password active.
Available Unit Mode setpoint = TEST
A test menu can then be selected to allow activation of the outputs. It is possible to
switch each digital output ON or OFF and set the analog outputs to any value.
Chilled Water Pump Control
Operation of the evaporator pump is controlled by the state-transition diagram shown
below.
Compressor Control
Compressor Sequencing
This section defines which compressor is the next one to start or stop. The next section
defines when the start, or stop, is to occur.
Compressor sequencing is based primarily on compressor run-hours and starts.
Compressors that have less starts will start before those with more starts. Compressors
that have more run-hours will shut off before those with less run-hours. In the event of
a tie on number of starts, the lower numbered compressor starts first. In the event of a
tie on run-hours, the lower numbered compressor shuts off first.
If possible, the number of running compressors on each circuit will be balanced. If a
circuit is unavailable for any reason, the other circuit is allowed to stage on all
compressors.
OFF
RUN
START
TEST:
Flow OK for
Evap Recirc Time
TEST:
Unit State=OFF
&
All Comp State=OFF
&
NO Evap water freeze condition
TEST:
Unit State = AUTO
AND
At least one circuit is enabled for start
OR
Evap water freeze condition
TEST:
Unit State=OFF
&
All Comp State=OFF
&
NO Evap water freeze condition
Power ON
Summary of Contents for AGZ026BS
Page 103: ...IOMM AGZ 5 AGZ 026B through 130B 103...
Page 104: ...104 AGZ 026B through 130B IOMM AGZ 5...
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